diff --git a/doc/whats_new/v1.3.rst b/doc/whats_new/v1.3.rst
index 8d39ca2fed143..e0df3c1beba4b 100644
--- a/doc/whats_new/v1.3.rst
+++ b/doc/whats_new/v1.3.rst
@@ -23,6 +23,12 @@ Changelog
   :attr:`sklearn.neighbors.KDTree.valid_metrics` as public class attributes.
   :pr:`26754` by :user:`Julien Jerphanion <jjerphan>`.
 
+:mod:`sklearn.tree`
+...................
+
+- |Fix| :func:`tree.plot_tree` now accepts `class_names=True` as documented.
+  :pr:`26903` by :user:`Thomas Roehr <2maz>`
+
 .. _changes_1_3:
 
 Version 1.3.0
diff --git a/sklearn/tree/_export.py b/sklearn/tree/_export.py
index 02f8ea81404c7..c89333aa49831 100644
--- a/sklearn/tree/_export.py
+++ b/sklearn/tree/_export.py
@@ -79,7 +79,7 @@ def __repr__(self):
         "decision_tree": [DecisionTreeClassifier, DecisionTreeRegressor],
         "max_depth": [Interval(Integral, 0, None, closed="left"), None],
         "feature_names": [list, None],
-        "class_names": [list, None],
+        "class_names": ["array-like", "boolean", None],
         "label": [StrOptions({"all", "root", "none"})],
         "filled": ["boolean"],
         "impurity": ["boolean"],
@@ -134,7 +134,7 @@ def plot_tree(
         Names of each of the features.
         If None, generic names will be used ("x[0]", "x[1]", ...).
 
-    class_names : list of str or bool, default=None
+    class_names : array-like of str or True, default=None
         Names of each of the target classes in ascending numerical order.
         Only relevant for classification and not supported for multi-output.
         If ``True``, shows a symbolic representation of the class name.